Ferrous alloy containing high manganese and chromium

ABSTRACT

A FERROUS ALLOY WHICH IS PARTICULARLY SUITABLE FOR USE AS A WELD DEPOSIT FOR STRUCTURAL MEMBERS. THE ALLOY, WHOSE CONSTITUENTS ARE LISTED BY WEIGHT PERCENT ARE AS FOLLOWS:   PERCENT CHROMIUM 1.0-4.0 CARBON 0.60-1.60 SILICON 0.30-1.00 MANGANESE 22.0-36.0 NICKEL 0-5.0 MOLYBDENUM (MAX.) 1.50 PHOSPHORUS (MAX.) 0.015 SULFUR (MAX) 0.015 IRON, BALANCE   EXHIBITS EXCELLENT MECHANICAL PROPERTIES ALONG WITH SUPERIOR RESISTANCE TO ABRASION AND IMPACT.

United States Patent O 'ice 3,556,777 FERROUS ALLOY CONTAINING HIGHMANGANESE AND CHROMIUM Howard J. Petry, West Alexandria, Ohio, assignorto Rexarc Incorporated, West Alexandria, Ohio, a corporation of Ohio NoDrawing. Filed Apr. 4, 1968, Ser. No. 718,941

Int. Cl. C22c 39/14 US. Cl. 75126 6 Claims ABSTRACT OF THE DISCLOSURE Aferrous alloy which is particularly suitable for use as a weld depositfor structural members. The alloy,

whose constituents are listed by weight percent are as follows:

Iron, balance exhibits excellent mechanical properties along withsuperior resistance to abrasion and impact.

BACKGROUND OF THE INVENTION The mining and highway constructionindustries have been two of the most rapidly growing industries in theUnited States. With this growth, there was an ever increasing need anddemand on the machinery performing the material moving tasks. Theincreased demands brought a greater awareness of the economics of theparticular methods for performing the assigned tasks. Such work variedfrom moving mud and rock to the extraction of the more corrosivematerials, coal and metallic ores.

In the design of the machinery to handle these heavy loads,consideration had to be given to the ability of the materials to resistthe wear and tear of'the constant use, and the abrasive action of thematerials to be moved. With this requirement, designers turned to suchalloy steels as the A181 high strength low alloy steels and the Hadfieldmanganese steels.

As the industry grew and the machines became larger and more complex,fabrication and maintenance problems increased. Changes had to be madein the field, Components were replaced or repaired by conventionaltechniques such as welding. It was not uncommon to weld dissimilarsteels such as manganese steel, alloy steels and the high carbon steels.

To accomplish the foregoing, the industry turned to stainless weldingrods, manganese welding rods and other alloy materials. However, therods were inadequate. Crack failures, lowered mechanical properties ofresistance to mildly corrosive conditions, and generally metallurgicallyunsound structures resulted. To applicants knowledge, it was not untilthe development of the present invention that a suitable welding rod wasfound for the industry which possessed none of the foregoingshortcomings. Structures could now be properly welded without cracks,reduction in properties or loss of corrosion resistance. Further, thewelded areas have both impact and abrasion resistance comparable to thestructural plates.

3,556,777 Patented Jan. 19, 1971 BRIEF SUMMARY OF THE INVENTION In thepreferred practice of this invention, alloying constituents on the orderof 27-50% are added to a ferrous base to produce an alloy which can beworked, by forging, rolling or extruding, to form a rod or wire suitablefor use in welding. Specifically, the principal alloying constituentsare manganese, carbon, nickel, chromium and optionally molybdenum. Thelimit of said additions are as follows:

Percent Carbon .60-1.6O Silicon .30- Manganese 22.0-360 Nickel 0-5.0Chromium 1.0-4.0 Molybdenum (max.) 1.50 Phosphorus (max.) .015 Sulfur(max.) .015

Iron, balance.

The preferred range of the alloying constituents are as follows:

Percent Manganese 22.0-28.0 Carbon 0.70-l.2 Silicon 0.30-1 .0 Nickel3.0-5 .0 Chromium 1.5-3 .0 Molybdenum 0.5-1.5 Phosphorus (max.) .015Sulfur (max.) .015

Iron, balance.

DETAILED DESCRIPTION OF THE INVENTION It should be apparent from theforegoing that the principal application of the ferrous alloy of thisinvention lies with its ability to form sound welds in joiningstructural alloy steel plates. However, it is not intended that thisalloy be so limited as other uses will become apparent to those skilledin the art. Since the alloy of this invention can be forged and rolledinto various shapes, the versatility of the alloy becomes more apparent.However, for convenience, the invention will be described with referenceto the particular application of welding rods. By welding rods, I intendto include both coated rods for manual use and bare wire for submergedare use.

A fabricated structure can be analogized to that of a chain wherein anew link has been inserted or substituted. To return the chain to itsformer capabilities, the new link has to be at least as good as thebalance of the chain links. This in essence was the problem facing theprior artproduction of welds comparable to the primary structure.

In an attempt to improve the weld structure of fabricated products, theprior art turned to stainless and alloy steels. The stainless steels,while high in chromium to offer excellent corrosion resistance, did notgive to the structure the required resistance to abrasion and impact.Further, the strength levels were well below the strength of the primarystructure.

Since abrasion resistance is one of the most desirable properties inthis area, the prior art began directing its attention to the 13%manganese Hadfield steels. This was due to the acknowledged effect ofmanganese on the hardenability of steels. Such steels were not withouttheir shortcomings, however. Typically, in welding operation, the basemetals and welding rods are melted and fused forming a distincttransition zone between the structures to be joined. Due to this meltingand fusion, a rapid migration or diffusion of the manganese occurs,thereby depleting portions of said zone of manganese. And, an

alloy content of about 50-10% manganese is generally poor. This isbelieved to be the result of an unstable austenitic crystallinestructure.

Since elemental migration or diffusion is a necessary incident towelding, it was proposed that higher manganese be employed to avoid theabove recited critical range. However, a further restriction placed uponthe prior art was the general belief that relatively low carbon valueswere necessary. For example, with 14% manganese electrode, carbon inexcess of 70% tended to decrease the usefulness of the alloy. Further,in the welding alloy proposed in US. Pat. No. 3,266,876, issued to DeLong et al., a maximum limit of 1% carbon was imposed on a 31% manganesesteel.

It was discovered by the present invention that with the particularcombination of elements, carbon up to 1.60% could be tolerated withoutcracking. It will be obvious to those skilled in the art that carbon isthe least expensive of the recited alloy additions and is quiteeffective in contributing to the hardness and wear resistance of thealloy. Hence, the present alloy is not only effective but relativelyinexpensive. It yields consistently high mechanical properties which areso essential to welding high strength structural plates.

The remaining alloy additions also contribute to the realization of thesuperior properties found in the alloy of this invention. Molybdenum,for example, which may be used With or to the exclusion of nickel, addsto the tensile strength of the weld deposits and further contributes toproducing a desirable fine grained structure. The chromium is essentialnot only to provide an assembled structure which is resistant to mildlycorrosive conditions, but it aids in tying up a portion of the carbon ascarbides.

A typical welding alloy having a composition within the alloying rangesset forth above is as follows:

Carbon .86 Silicon .35 Manganese 22.05 Nickel 3.18 Chromium 1.63Phosphorus 0.12 Sulfur 0.12 Iron, balance,

was found to possess these properties:

Tensile strength (k.p.s.i.) 144.2 Yield strength (k.p.s.i.) 96.5Elongation (percent) in 1.4" 33.6

Impact (ft.-lbs.)

the as deposited hardness Was R -50. This was hardened to R 45-50.

It should be apparent from the foregoing that modifications may be madein the invention without departing from the spirit and scope thereof.Therefore, no limitation is intended to be imposed herein, except as setforth in the appended claims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A Weld deposit for ferrous metallic structural members comprising aferrous alloy consisting essentially by weight of about .60'-l.60%carbon, about .30'l.0% silicon, about 22.0-36.0% manganese, up to about5% nickel, about 1.0-4.0% chromium, up to about 1.50 molybdenum, and thebalance substantially iron, said deposit characterized by the propertiesof being resistant to cracking, and possessing high mechanical strengthand resistance to abrasion.

2. The alloy claimed in claim 1 wherein the carbon is present in anamount of about 0 .701.2%.

3. The alloy claimed in claim 2 wherein manganese is present in amountof about 22.0-28.0%, nickel in amount of about 1.5-3.0%.

4. A ferrous alloy consisting essentially by weight of about .60-1.60%carbon, about 30-10% silicon, about 22.0-36.0% manganese, up to about 5%nickel, about 10-40% chromium, up to about 1.50% molybdenum, and thebalance substantially iron, whereby said alloy exhibits excellentmechanical properties along with superior resistance to abrasion andimpact.

5. The ferrous alloy claimed in claim 4- wherein the carbon is presentin an amount of about -12%.

6. The ferrous alloy claimed in claim 5 wherein manganese is present inan amount of about 22.0-28.071, nickel in an amount of about 30-50%, andchromium in an amount of about 1.5-3.0%.

References Cited UNITED STATES PATENTS 1,333,151 3/1920 Becket -126B1,561,306 11/1925 Brace 75--128A 2,038,178 4/1936 Jerabek 75-12312,156,299 5/1939 Leitner 75-126B 2,184,305 12/1939 Kropf 75-126B2,357,885 9/1944 Franks 75-1263 HYLAND BIZOT, Primary Examiner US. Cl.X.R. 75128

